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Comment by pmiller2 | Hacker News Reader

I was interested to learn that the loudest possible sound on Earth would be 194 db. [0] Krakatoa apparently "only" clocked in at 180 db, meaning the loudest possible sound is about 5x louder than said eruption.

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The article states that the sound from Krakatoa was well over the 194dB limit.

If a reader were skimming the article, they might have missed that the 172 decibel "reading" was measured at a gasworks 100 miles from the eruption!

194 db is the loudest possible sound, where sound is an oscillating pressure wave. Pressure above 194 db become Shock or blast waves, which are a pressure pulse.

https://waitbutwhy.com/2016/03/sound.html

IIRC A 10 Db increase in SPL is perceived by most people as a doubling of "volume".

thr article mentions this too... its hard to get a feel for log scales lol.

Yeah, it's funny how humans don't really comprehend logarithmic or exponential growth, yet, the whole reason we use a log scale for stuff like sound pressure is that our nervous system has a logarithmic response curve.

TIL how the decibel scale works.

Genuine question, how's the difference between 194db and 180db only 5x? Shouldn't it be more than 10x?

The decibel is defined as a tenth of the log10 of power, so power doubles every ~3dB. Amplitude and pressure are proportional to the root of power, so amplitude doubles every ~6db. Loudness is roughly proportional to the root of amplitude so it doubles every ~9dB.

This leads to confusion when people don't specify which quantity they are comparing.

Thank you for that explanation. Based on that, the original poster meant 194db is 5x the power of 180db but only ~1.6x loud?

Increase of 14db would be an increase in perceived loudness of ~2.6x

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